Writing instrument



FIG. 1 is a front, perspective view of a writing instrument showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The features shown in broken lines depict environmental subject matter only and form no part of the claimed design. The bold, long short broken lines on the top of the barrel underneath the push button define the bounds of the claimed design and form no part thereof. 

CLAIM The ornamental design for a writing instrument, as shown and described. 